Background: In patients with luminal-type breast cancer (positive for ER and/or PgR), a complete consensus on the threshold indication for a combination of chemotherapy and endocrine therapy has not been achieved, especially for patients with HER2-negative luminal type (HNLT). Girdin, an actin-binding Akt substrate, plays a crucial role in the migration of cancer cells. This study examined the expression of Girdin in relation to clinicopathological features and other immunohistochemical markers (HER2, Ki-67), especially in patients with HNLT breast cancer.
Methods: One hundred one breast cancer patients who underwent surgery were evaluated. Immunohistochemical staining was performed for Girdin and other biomarkers, such as ER, PgR, HER2, and Ki-67.
Results: Positive expression of Girdin was observed in 26 patients. The expression of Girdin was significantly associated with the incidence of lymph node metastases (p = 0.001). Among the other examined biomarkers, positive expression of Ki-67 also showed a significant association with the incidence of lymph node metastases (p = 0.04). In the HNLT breast cancer patients (n = 73), the 5-year recurrence-free survival rate was significantly lower (57 %) in patients with positive expression of both Girdin and Ki-67 than the rate in other patients (92 %) (p = 0.002).
Conclusion: This study demonstrated that the expression of Girdin in invasive breast cancer is strongly associated with lymph node metastasis. The expression status of Girdin and Ki-67 can be a useful biomarker in stratifying patients with HNLT breast cancer into those with high risk of recurrence and the need for additional chemotherapy.